Methods and apparatus for uplink resource assignment

Abstract

The present invention relates to a method for uplink transmission performed in a wireless terminal served by a radio network node of a wireless communication system and corresponding radio network node method. The method comprises receiving an assignment for an uplink transmission from the radio network node. The method also comprises determining alternative usages of the assignment based on the received assignment. Each alternative usage is associated with a different DMRS. The method further comprises selecting a usage among the alternative usages of the assignment, and applying the selected usage when transmitting uplink data to the radio network node. The method also comprises transmitting the DMRS associated with the selected usage.

1 . A method for uplink transmission performed in a wireless terminal served by a radio network node of a wireless communication system, the method comprising:
 receiving an assignment for an uplink transmission from the radio network node,   determining alternative usages of the assignment based on the received assignment, each alternative usage being associated with a different demodulation reference signal,   selecting a usage among the alternative usages of the assignment,   applying the selected usage when transmitting uplink data to the radio network node, and   transmitting the demodulation reference signal associated with the selected usage.   
     
     
         2 . The method according to  claim 1 , further comprising:
 receiving configuration information from the radio network node configuring at least one of the following: how to determine the alternative usages of the assignment; and the associations between the alternative usages and the different demodulation reference signals.   
     
     
         3 . The method according to  claim 2 , wherein the configuration information is received in at least one of the following: a system information message, a radio resource control reconfiguration message, and a downlink control information message. 
     
     
         4 . The method according to  claim 1 , wherein the alternative usages of the assignment comprise at least one of: alternative usages of assigned time-frequency resources, and alternative usages of assigned transmission formats. 
     
     
         5 . The method according to  claim 1 , wherein the different demodulation reference signals associated with the alternative usages differs with respect to at least one of: a cyclic shift of the demodulation reference signal, an allocation of the demodulation reference signal, and a rank selection determining on what layers the demodulation reference signal is transmitted. 
     
     
         6 . The method according to  claim 1 , wherein selecting the usage is based on at least one of: a capability of the wireless terminal, a transmission mode of the wireless terminal, a downlink control information format of the assignment, resources on which the assignment is received, a rank granted in the assignment. 
     
     
         7 . The method according to  claim 1 , wherein the alternative usages are determined based on a function of the received assignment. 
     
     
         8 . A method for decoding uplink data received from a wireless terminal, the method being performed in a radio network node of a wireless communication system serving the wireless terminal, the method comprising:
 transmitting an assignment for an uplink transmission to the wireless terminal,   receiving a demodulation reference signal and uplink data from the wireless terminal in response to the assignment,   correlating the received demodulation reference signal with at least one of a plurality of different demodulation reference signals, each different demodulation reference signal being associated with an alternative usage of the assignment,   selecting a probable demodulation reference signal among the plurality of different demodulation reference signals based on the correlation, and   decoding the uplink data using the alternative usage associated with the probable demodulation reference signal.   
     
     
         9 . The method according to  claim 8 , further comprising:
 performing a cyclic redundancy check of the decoded uplink data, and if the cyclic redundancy check indicates an error in the decoded uplink data,   selecting a new probable demodulation reference signal based on the correlation, and   decoding the uplink data using the alternative usage associated with the new probable demodulation reference signal.   
     
     
         10 . The method according to  claim 8 , further comprising:
 transmitting configuration information to the wireless terminal configuring at least one of the following: how to determine the alternative usage of the assignment; and the associations between the alternative usages and the different demodulation reference signals.   
     
     
         11 . The method according to  claim 10 , wherein the configuration information is transmitted in at least one of the following: a system information message, a radio resource control reconfiguration message, a downlink control information message. 
     
     
         12 . The method according to  claim 8 , wherein the alternative usage of the assignment comprises at least one of: alternative usages of assigned time-frequency resources, and alternative usages of assigned transmission formats. 
     
     
         13 . The method according to  claim 8 , wherein the different demodulation reference signals associated with the alternative usages differs with respect to at least one of: a cyclic shift of the demodulation reference signal, an allocation of the demodulation reference signal, and a rank selection determining on what layers the demodulation reference signal is transmitted. 
     
     
         14 . A wireless terminal for uplink transmission configured to be served by a radio network node of a wireless communication system, the wireless terminal comprising a processor, a memory, a receiver, and a transmitter, said memory containing instructions executable by said processor whereby said wireless terminal is operative to:
 receive an assignment for an uplink transmission from the radio network node via the receiver,   determine alternative usages of the assignment based on the received assignment, each alternative usage being associated with a different demodulation reference signal,   select a usage among the alternative usages of the assignment,   apply the selected usage when transmitting uplink data to the radio network node via the transmitter, and   transmit the demodulation reference signal associated with the selected usage via the transmitter.   
     
     
         15 . The wireless terminal according to  claim 14 , wherein said memory contains instructions executable by said processor whereby said wireless terminal is further operative to:
 receive configuration information from the radio network node via the receiver, configuring at least one of the following: how to determine the alternative usages of the assignment; and the associations between the alternative usages and the different demodulation reference signals.   
     
     
         16 . The wireless terminal according to  claim 15 , wherein said memory contains instructions executable by said processor whereby said wireless terminal is further operative to receive the configuration information in at least one of the following: a system information message, a radio resource control reconfiguration message, and a downlink control information message. 
     
     
         17 . The wireless terminal according to  claim 14 , wherein the alternative usages of the assignment comprise at least one of: alternative usages of assigned time-frequency resources, and alternative usages of assigned transmission formats. 
     
     
         18 . The wireless terminal according to  claim 14 , wherein the different demodulation reference signals associated with the alternative usages differs with respect to at least one of: a cyclic shift of the demodulation reference signal, an allocation of the demodulation reference signal, and a rank selection determining on what layers the demodulation reference signal is transmitted. 
     
     
         19 . The wireless terminal according to  claim 14 , wherein said memory contains instructions executable by said processor whereby said wireless terminal is further operative to select the usage based on at least one of: a capability of the wireless terminal, a transmission mode of the wireless terminal, a downlink control information format of the assignment, resources on which the assignment is received, a rank granted in the assignment. 
     
     
         20 . The wireless terminal according to  claim 14 , wherein said memory contains instructions executable by said processor whereby said wireless terminal is further operative to determine the alternative usages based on a function of the received assignment. 
     
     
         21 . A radio network node of a wireless communication system configured to decode uplink data received from a wireless terminal served by the radio network node, the radio network node comprising a processor, a memory, a transmitter, and a receiver, said memory containing instructions executable by said processor whereby said radio network node is operative to:
 transmit an assignment for an uplink transmission to the wireless terminal via the transmitter,   receive a demodulation reference signal and uplink data from the wireless terminal via the receiver in response to the assignment,   correlate the received demodulation reference signal with at least one of a plurality of different demodulation reference signals, each different demodulation reference signal being associated with an alternative usage of the assignment,   select a probable demodulation reference signal among the plurality of different demodulation reference signals based on the correlation, and   decode the received uplink data using the alternative usage associated with the probable demodulation reference signal.   
     
     
         22 . The radio network node according to  claim 21 , wherein said memory contains instructions executable by said processor whereby said radio network node is further operative to:
 perform a cyclic redundancy check of the decoded uplink data, and if the cyclic redundancy check indicates an error in the decoded uplink data,   select a new probable demodulation reference signal based on the correlation, and   decode the uplink data using the alternative usage associated with the new probable demodulation reference signal.   
     
     
         23 . The radio network node according to  claim 21 , wherein said memory contains instructions executable by said processor whereby said radio network node is further operative to:
 transmit configuration information via the transmitter to the wireless terminal configuring at least one of the following: how to determine the alternative usage of the assignment; and the associations between the alternative usages and the different demodulation reference signals.   
     
     
         24 . The radio network node according to  claim 23 , wherein said memory contains instructions executable by said processor whereby said radio network node is further operative to transmit the configuration information in at least one of the following: a system information message, a radio resource control reconfiguration message, a downlink control information message. 
     
     
         25 . The radio network node according to  claim 21 , wherein the alternative usage of the assignment comprises at least one of: alternative usages of assigned time-frequency resources, and alternative usages of assigned transmission formats. 
     
     
         26 . The radio network node according to  claim 21 , wherein the different demodulation reference signals associated with the alternative usages differs with respect to at least one of: a cyclic shift of the demodulation reference signal, an allocation of the demodulation reference signal, and a rank selection determining on what layers the demodulation reference signal is transmitted. 
     
     
         27 . (canceled) 
     
     
         28 . (canceled) 
     
     
         29 . A non-transitory computer readable medium storing computer readable code which when run on a wireless terminal causes the wireless terminal to:
 receive an assignment for an uplink transmission from a radio network node,   determine alternative usages of the assignment based on the received assignment, each alternative usage being associated with a different demodulation reference signal,   select a usage among the alternative usages of the assignment,   apply the selected usage when transmitting uplink data to the radio network node, and   transmit the demodulation reference signal associated with the selected usage.   
     
     
         30 . (canceled) 
     
     
         31 . A non-transitory computer readable medium storing computer readable code which when run on a radio network node causes the radio network node to:
 transmit an assignment for an uplink transmission to the wireless terminal,   receive a demodulation reference signal and uplink data from the wireless terminal in response to the assignment,   correlate the received demodulation reference signal with at least one of a plurality of different demodulation reference signals, each different demodulation reference signal being associated with an alternative usage of the assignment,   select a probable demodulation reference signal among the plurality of different demodulation reference signals based on the correlation, and   decode the uplink data using the alternative usage associated with the probable demodulation reference signal.   
     
     
         32 . (canceled)